1. Field of the Invention
The present invention relates to a sealing device for an elevator, which seals a gap between a doorway member provided in the gate of an elevator and a door device provided adjacent to the doorway member.
2. Description of the Related Art
The gate of an elevator is provided between an elevator hall in a building and an elevator shaft. The doorway member is set in the gate. A hall door is installed adjacent to the doorway member. The hall door opens when the cage, which moves up and down in the shaft, arrives at an elevator hall, thus enabling passengers to get on or off the cage. Then, when the cage departs from the elevator hall, the door closes.
In general, the hall door of an elevator is opened or closed by rolling hanger rollers provided at an upper section of the door along a hanger rail provided at an upper portion of the doorway member. In order for the hall door to smoothly open and close, a gap is created between the hall door and a three-sided frame of the doorway member, or a doorsill.
In case of a fire occurring in the building, the smoke and toxic gas due to the fire can enter the shaft of the elevator through the gap in the hall door. As a result, the smoke may spread to some other floors through the gap of the hall door of these floors, thus exposing the residents to danger.
In order to avoid such situations, some elevators are equipped with a sealing mechanism installed for the hall door, or a smoke shutting facilities such as a shutter, door and screen installed near the hall door. However, when such smoke shutting facilities that include a shutter are provided, the production cost is naturally increased. Further, the storage space and guide mechanisms that are provided afterwards deteriorate the appearance of the elevator.
As a method of prohibiting the deterioration of the appearance, there is a widely popular technique, in which a sealing mechanism is set in the hall door such that the gap between the hall door and the doorway member is shut while the door is closed. There have been a number of techniques proposed as the sealing mechanism. According to these techniques, a rubber or some other elastic member is mounted on the circumference of the door to seal the gap by the elastic member as it is pressed between the door and doorway when the door is closed. Of the members to be sealed, provided around the door, a doorstop portion and a rear side end portion of the door can be pressed by bringing the door into contact with the seal member just before the door is closed. Therefore, in connection with these members, the gaps can be sealed with a relatively simple sealing mechanism that uses a rubber, a metal plate, etc.
On the other hand, in the upper section of the door and the doorsill portion, such seal member, if a rubber or a thin metal plate is simply mounted, entails the following problem. That is, the seal member and the door are in contact with each other at all times and they slide on against each other when opening or closing the door. Therefore, the seal member wears out or loses stiffness to deteriorate its smoke shutting performance. Further, as the slide resistance is increased, the door can no longer be opened or closed smoothly or the noise created when the door slides may be increased.
Jpn. Pat. Appln. KOKAI Publications Nos. 6-234488 and 7-76477 each disclose a mechanism for shutting the gap in the upper section of the door, in which the seal member is brought into contact with the member on the other side when the door has been closed. In this mechanism, the seal member is set inclined and mounted on the upper section of the door. This mechanism is designed to inhibit the seal member and the other member from contacting with each other while opening or closing the door. In this manner, the door can be opened or closed smoothly and at the same time, the damage to the seal member is prevented.
Apart from the above, there has been proposed a technique in which the seal member does not slide at all times but it is made abut against the other member by an actuator only when a fire occurs, for example, in Jpn. Pat. Appln. KOKAI Publication No. 2003-34481. According to this document, the attracting force of an electromagnet is released in reply to an output made by a smoke sensor, and the gap shut member is pushed out with a spring to shut the gap.
Further, Jpn. Pat. Appln. KOKAI Publication No. 7-247086 discloses a technique that provides a smoke shutting mechanism that bends in a labyrinth-like manner around the door. This mechanism is designed to interrupt the smoke by making the gap into a labyrinth-like form. With this mechanism, there is not sliding portion, and therefore the seal member is never worn out.
However, the invention having the configurations disclosed in Jpn. Pat. Appln. KOKAI Publication No. 6-234488 or 7-76477 requires an extra space in the installation in the height direction, for inclining the seal member. Therefore, it is difficult to carry out the reform of adding the smoke shutting mechanism to an already installed door while retaining the measurements of the already installed door and its guide mechanism. Further, since the seal member is set inclined, it is difficult to appropriately adjust the pressing force and contact area both of the seal members provided for the doorstop of the door and the inclined seal member.
As a result, it takes a lot of time and labor to adjust the seal member. Further, with these inventions, the inclined seal member is pressed, and therefore a component of force is created in the direction in which the door is opened, by means of the reactive force of the seal member. Consequently, it requires a large force to close the door and maintain the door closed. As a result, the driving mechanism and the mechanism for closing the door are increased in size.
The mechanism disclosed in Jpn. Pat. Appln. KOKAI Publication No. 2003-34481 requires a large space for installing the actuator. Further, this mechanism requires, for example, a control device for processing output signals from the smoke sensor, a wiring for the actuator and a recovery mechanism that is used to recover the mechanism after the sealing mechanism has been operated due to a power failure, an error by the smoke sensor, etc. Hence, the device becomes complicated.
In the mechanism disclosed in Jpn. Pat. Appln. KOKAI Publication No. 7-247086, the gap must be sufficiently narrow in order for the smoke shutting function to work appropriately. To maintain the narrow gap, high-precision parts are required. This mechanism, if installed not precisely, creates noise when members slide on each other, and therefore it is very difficult to adjust the set positions of the members when installed.